Hand-held grass trimmers are known, such as shown and described in U.S. Pat. No. 3,971,130 as well as German Patent No. De2,718,355, U.S. Pat. No. 4,202,094 to Kalmar and U.S. Pat. No. 4,641,431 to Leming et al. U.S. Pat. No. 3,971,130 and the German Patent No. De 2,718,355 both relate to a scissors type of grass and weed trimmer while U.S. Pat. No. 4,202,094 relates to a rotating flexible mono filament arrangement attached to a hand drill. U.S. Pat. No. 4,641,431 is directed to a hand-held electric hedge trimmer using a wire whip.
The present invention is directed to an improvement over the prior art constructions in both operation and safety and utilizes either a flexible line, such as a filament nylon line, or a rotating blade.
It is an object of the present invention to provide a full circle guard for the rotating flexible line or cutter blade which results in an improved safety for the operator as well as any person or thing in the vicinity of the trimming activity.
It is another object of the present invention to provide a hand-held grass/weed trimmer which makes it possible to accomplish precise trimming without cutting plants and shrubbery adjacent thereto.
It is still another object in the present invention to provide a guard member which prevents objects such as rocks, stone walls and, posts from entering into the area of the cutting line or cutter, thus abrading and severing the cutting member, and necessitating time consuming and costly replacement.
Another object of the present invention is to provide a full circle guard member which reduces the hazard of damage or injury to the operator or other persons caused by inadvertently propelling stones, rocks and other debris beyond the confines of a guard wall. Additionally, the configuration of the guard with spaced tines having rather limited openings therein prevents objects with relatively large masses from entering into the cutting area, and being propelled out of the guard with considerable force to strike a person, or persons, in the vicinity.
A further object of the present invention is to provide the full circle guard arrangement for a hand-held grass/weed trimmer in which a portion of the guard can be removed for up-to-the-edge trimming when using the device in connection with a nylon line cutting member.
Another feature of the present invention is to provide plurality of variations in detachable hub designs for removably securing either a flexible cutting line or a rigid cutting blade to the hub. The attachment to the motor shaft is accomplished by both mechanical interlock as well as a slight distortion of a slightly resilient retainer cap caused by an interference fit when it meets with a mounting hub and traps the cutting member under compression pressure.